Added a new playAtActualSpeed option to GPUImageMovie to have it play…

…back at the actual speed of the source movie. The timing isn't perfect on this yet.
mramsden · Sep 5, 2012 · fa8ea2f · fa8ea2f
1 parent 202ce48
commit fa8ea2f
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Showing 3 changed files with 37 additions and 2 deletions.
diff --git a/examples/SimpleVideoFileFilter/SimpleVideoFileFilter/SimpleVideoFileFilterViewController.m b/examples/SimpleVideoFileFilter/SimpleVideoFileFilter/SimpleVideoFileFilterViewController.m
@@ -25,6 +25,7 @@ - (void)viewDidLoad
 
     movieFile = [[GPUImageMovie alloc] initWithURL:sampleURL];
     movieFile.runBenchmark = YES;
+    movieFile.playAtActualSpeed = YES;
 //    filter = [[GPUImagePixellateFilter alloc] init];
 //    filter = [[GPUImageUnsharpMaskFilter alloc] init];
 
@@ -86,7 +87,8 @@ - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interface
 
 - (IBAction)updatePixelWidth:(id)sender
 {
-    [(GPUImageUnsharpMaskFilter *)filter setIntensity:[(UISlider *)sender value]];
+//    [(GPUImageUnsharpMaskFilter *)filter setIntensity:[(UISlider *)sender value]];
+    [(GPUImageDissolveBlendFilter *)filter setMix:[(UISlider *)sender value]];
 //    pixellateFilter.fractionalWidthOfAPixel = [(UISlider *)sender value];
 }
 

diff --git a/framework/Source/GPUImageMovie.h b/framework/Source/GPUImageMovie.h
@@ -14,6 +14,10 @@
  */
 @property(readwrite, nonatomic) BOOL runBenchmark;
 
+/** This determines whether to play back a movie as fast as the frames can be processed, or if the original speed of the movie should be respected. Defaults to NO.
+ */
+@property(readwrite, nonatomic) BOOL playAtActualSpeed;
+
 /// @name Initialization and teardown
 - (id)initWithAsset:(AVAsset *)asset;
 - (id)initWithURL:(NSURL *)url;

diff --git a/framework/Source/GPUImageMovie.m b/framework/Source/GPUImageMovie.m
@@ -7,6 +7,8 @@ @interface GPUImageMovie ()
     GPUImageMovieWriter *synchronizedMovieWriter;
     CVOpenGLESTextureCacheRef coreVideoTextureCache;
     AVAssetReader *reader;
+    CMTime previousFrameTime;
+    CFAbsoluteTime previousActualFrameTime;
 }
 
 - (void)processAsset;
@@ -18,6 +20,7 @@ @implementation GPUImageMovie
 @synthesize url = _url;
 @synthesize asset = _asset;
 @synthesize runBenchmark = _runBenchmark;
+@synthesize playAtActualSpeed = _playAtActualSpeed;
 
 #pragma mark -
 #pragma mark Initialization and teardown
@@ -92,10 +95,14 @@ - (void)enableSynchronizedEncodingUsingMovieWriter:(GPUImageMovieWriter *)movieW
 
 - (void)startProcessing
 {
-    if(self.url == nil) {
+    if(self.url == nil)
+    {
       [self processAsset];
       return;
     }
+
+    previousFrameTime = kCMTimeZero;
+    previousActualFrameTime = CFAbsoluteTimeGetCurrent();
 
     NSDictionary *inputOptions = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES] forKey:AVURLAssetPreferPreciseDurationAndTimingKey];
     AVURLAsset *inputAsset = [[AVURLAsset alloc] initWithURL:self.url options:inputOptions];    
@@ -181,6 +188,25 @@ - (void)readNextVideoFrameFromOutput:(AVAssetReaderTrackOutput *)readerVideoTrac
         CMSampleBufferRef sampleBufferRef = [readerVideoTrackOutput copyNextSampleBuffer];
         if (sampleBufferRef) 
         {
+            if (_playAtActualSpeed)
+            {
+                // Do this outside of the video processing queue to not slow that down while waiting
+                CMTime currentSampleTime = CMSampleBufferGetOutputPresentationTimeStamp(sampleBufferRef);
+                CMTime differenceFromLastFrame = CMTimeSubtract(currentSampleTime, previousFrameTime);
+                CFAbsoluteTime currentActualTime = CFAbsoluteTimeGetCurrent();
+
+                CGFloat frameTimeDifference = CMTimeGetSeconds(differenceFromLastFrame);
+                CGFloat actualTimeDifference = currentActualTime - previousActualFrameTime;
+
+                if (frameTimeDifference > actualTimeDifference)
+                {
+                    usleep(1000000.0 * (frameTimeDifference - actualTimeDifference));
+                }
+
+                previousFrameTime = currentSampleTime;
+                previousActualFrameTime = CFAbsoluteTimeGetCurrent();
+            }
+
             __unsafe_unretained GPUImageMovie *weakSelf = self;
             runSynchronouslyOnVideoProcessingQueue(^{
                 [weakSelf processMovieFrame:sampleBufferRef];
@@ -230,6 +256,9 @@ - (void)readNextAudioSampleFromOutput:(AVAssetReaderTrackOutput *)readerAudioTra
 
 - (void)processMovieFrame:(CMSampleBufferRef)movieSampleBuffer; 
 {
+//    CMTimeGetSeconds
+//    CMTimeSubtract
+
     CMTime currentSampleTime = CMSampleBufferGetOutputPresentationTimeStamp(movieSampleBuffer);
     CVImageBufferRef movieFrame = CMSampleBufferGetImageBuffer(movieSampleBuffer);